The present invention relates to a side airbag apparatus having an airbag that is inflated and deployed in a space on a side of an occupant.
Typically, a side airbag apparatus inflates and deploys an airbag in a space on a side of an occupant when an impact of a magnitude greater than or equal to a predetermined value is applied to the body side portion of a vehicle. By reducing the impact applied to the occupant with the inflated airbag, the apparatus protects the head, the thorax, or the lumbar region. In such a side airbag apparatus, gas is injected to the interior of the airbag by a gas generator so that the airbag is instantly inflated and deployed (for example, Japanese Laid-Open Patent Publication No. 2006-137398).
In this type of side airbag apparatus, sufficient protection of the occupant cannot be achieved simply by inflating and deploying the airbag. That is, the airbag needs to be inflated and deployed into an intended state at an intended location. Therefore, in addition to allowing the airbag to be instantly inflated and deployed, it is important to control the behavior of the airbag in an attempt to inflate and deploy the airbag into a desired condition at a desired position.
In a typical side airbag apparatus, a folded airbag is fixed to a surface of the seat frame of a seatback on a side closer to the outside of the vehicle. The pressure of gas discharged from the gas generator causes the airbag to break through the cover of the seatback and to be inflated and deployed toward the front of the vehicle.
The side airbag apparatus of the above publication has a flat deployment stabilizing plate (guiding member), which guides the airbag such that the airbag is inflated and deployed toward the front of the vehicle. The apparatus has a vertically extending rotary shaft at the front edge of an outer surface (a surface closer to the outside of the vehicle) of the seatback frame (seat frame) of the vehicle. The deployment stabilizing plate is supported by the rotary shaft so as to be pivotable about the rotary shaft. A stopper is fixed to the seat frame at a position inside the deployment stabilizing plate (at a position closer to the center of the vehicle). Inward pivoting of the deployment stabilizing plate is restricted by the stopper.
When an occupant sits in the vehicle seat, the deployment stabilizing plate can receive a force acting from inside the vehicle toward the outside. In this case, the deployment stabilizing plate is pivoted outward to reduce the pressure applied to the occupant, thereby preventing the occupant from being disturbed by the sensation from the seat. On the other hand, when the airbag is inflated and deployed, the deployment stabilizing plate receives a force in a direction from the outside of the vehicle toward the interior. In this case, inward pivoting of the deployment stabilizing plate is restricted by the stopper. This inhibits the airbag from being inflated and deployed toward the interior of the vehicle, and the airbag is guided to be inflated and deployed toward the front of the airbag.
However, after a force acting from inside the vehicle toward the outside is applied to the deployment stabilizing plate of the apparatus of the above publication, and pivots the plate to a position closer to the outside of vehicle, the plate does not return to the original position. Thus, when the airbag is inflated and deployed, the deployment stabilizing plate interferes with the airbag. This results in variations in the direction of inflation and deployment.